13. правильно совместите придаточные предложения с главными: a) if you write a letter … a) … they would have receive it by now. b) if you wrote a letter … b) … they would receive it soon. c) if you had written the letter … c) … tell them the news.

a) If you write a letter tell them the news.                       
      b) If you wrote a letter they would receive it soon.    
   c) If you had written the letter they would have received it by now.